A variety of devices utilize pluggable transceivers to provide connectivity. Exemplary devices include optical network elements (SONET, SDH, OTN, etc.), Ethernet switches, routers, video devices, and the like. In an effort to decouple transceiver design and manufacturing from the underlying devices, various multi-source agreements (MSAs) have been defined to standardize pluggable transceivers. MSAs are agreements for specifications of transceivers agreed to by two or more vendors and promulgated for other vendors and network operators to utilize. MSAs allow other vendors to design transceivers to the same specifications reducing risk for vendors and operators, increasing flexibility, and accelerating the introduction of new technology. Exemplary MSAs include XFP, XPAK, XENPAK, X2, XFP-E, SFP, and SFP+. Additionally, new MSAs are emerging to address new services and advanced technology. Each MSA defines the transceiver's mechanical characteristics, management interfaces, electrical characteristics, optical characteristics, and thermal requirements. Because of MSA specifications, MSA-compliant transceivers are standardized among equipment vendors and network operators to support multiple sources for pluggable transceivers and interoperability. As such, MSA-compliant transceivers have become the dominant form of transmitters and receivers in the industry.
Advantageously, MSA-compliant pluggable transceivers ensure engineering re-use and compatibility between various applications and the physical media dependent transceivers. Further, equipment vendors realize streamlined manufacturing and inventory control by removing wavelength specific decisions from the manufacturing process. For example, all line cards are manufactured the same, and the MSA-compliant transceiver module with the desired wavelength (e.g. 850 nm, 1310 nm, 1550 nm, dense wave division multiplexed (DWDM), etc.) is used as a function of the specific application or development configuration. Network operators and service providers have adopted MSA-compliant transceivers to reduce sparing costs. Further, significant cost reductions are realized by MSA standardization of MSA-compliant transceivers because of multiple independent manufacturing sources.
The MSA specifications tightly define the mechanical characteristics, management interfaces, electrical characteristics, optical characteristics, and thermal requirements of pluggable transceivers. However, the MSA specifications, such as in the case of SFP, SFP+, etc., do not specify how the pluggable transceivers are ejected from a host device. The SFP transceiver is specified by a MSA from the SFF committee (available at www.sffcommittee.com). The SFP was designed after the gigabit interface converter (GBIC) interface, and allows greater port density (number of transceivers per inch along the edge of a mother board) than the GBIC, which is why SFP is also known as mini-GBIC. The related Small Form Factor (SFF) transceiver is similar in size to the SFP, but is soldered to the host board as a pin through-hole device, rather than plugged into an edge-card socket. Small form-factor pluggable transceivers offer a great deal of flexibility in limited spatial constraints. The ability to densely populate such transceivers is highly marketable for to add system capacity.
MSAs, such as the SFP MSA, identify features that must be present with respect to an ejector methodology. The ejector is a mechanism to add/remove a pluggable transceiver from a host system. Conventional designs for ejectors utilize the enclosure side with either a tabbed or bail latch ejector system. Tabbed and single-arm ejector designs limit the ejector's accessibility in that the ejector can only be engaged from one direction thereby limiting the ability to densely populate modules. Bail-style ejectors include an arm that folds over the front of the transceiver that engages an ejection actuator. A key disadvantage of bail-style ejectors is that they require the user to disconnect any cables or fibers connected to the module prior to actuation. Other disadvantages of bail-style ejector systems are their complexity, cost, and their inability to work with longer neck connector styles.
Thus an improved ejector methodology is needed for pluggable transceivers, such as the SFP transceiver, that allows ease of access, supports high density, and allows ejection with connected cables.